It is known to provide the storage and retrieval of digital information on magnetic tape in a format that is referred to as the DDS format which has developed through a number of versions. In a DDS tape drive, a magnetic tape cassette is loaded into the tape drive and the tape in the cassette is transported past a rotary head drum to record overlapping oblique tracks across the tape. The DDS format provides for a number of specific areas on the tape including a device area for loading and testing the tape, a system area that includes a tape log and a data area for recording user data. The tape log is provided to record tape usage information. The tape log is read when a tape cassette is loaded into the tape drive and the tape log is updated by being overwritten when the tape cassette is unloaded.
If problems occur during an update of the tape log, due to a head clog or a power cycle failure, then the log can be corrupted rendering it useless on subsequent tape loading operations. In addition, if the tape drive has had problems in writing data to the tape, it may be considered too risky to attempt an update of the tape log for fear of corrupting the log. In this case the cassette may be ejected without the current tape usage information being added to the log.